1. Field of the Invention
The present invention relates to a rotor of a dynamo-electric machine and, more specifically, to the structure of a rotor of an alternating current generator or an electric motor as a dynamo-electric machine for a vehicle.
2. Description of the Related Art
A rotor of a dynamo-electric machine having a rotor coil for generating a magnetic flux and a pole core made up of a first pole core body and a second pole core body provided so as to cover the rotor coil and having tooth-shaped magnetic poles projecting so as to mesh alternately with each other is widely known.
On the tooth-shaped magnetic poles, permanent magnets are attached. The object of attaching the permanent magnets to the tooth-shaped magnetic poles is to improve the output of a dynamo-electric machine by reducing magnetic flux leakage from the side surfaces of the adjacent tooth-shaped magnetic poles or from the inner peripheral surfaces thereof.
However, when the magnets are mounted, the weight of the entire tooth-shaped magnetic pole increases, and hence a centrifugal force generated by rotation of the rotor increases. In particular, when the weight at the distal ends of the tooth-shaped magnetic poles increases, deformation in the direction toward a stator increases. Therefore, it is necessary to increase an air gap between the rotor and the stator. However, the air gap is critical for the output, and the output increases as the air gap decreases.
Therefore in order to achieve further improvement of the output, it is necessary to fix the magnets so as to restrain deformation of the tooth-shaped magnetic poles.
There is provided a magnet retaining member for mounting the magnet to the tooth-shaped magnetic pole (For example, see JP-A-2001-086715). However, this magnet retaining member also has a risk that the magnet retaining member or the magnet itself may become damaged or may deviated due to increase in deformation of the tooth-shaped magnetic pole or vibration of the tooth-shaped magnetic pole caused by variations in the revolving number of the rotor.
In order to cope with this problem, in the related art, it is contemplated to absorb the movement of the magnets due to the centrifugal force by securing the magnets, which are mounted to the side surfaces of the respective adjacent tooth-shaped magnetic poles, with respect to each other with adhesive layers having high flexibility.
However, since the magnets are secured directly by the adhesive layers, a stress is exerted directly to the magnets.
In addition, a measure to insert flat plates having higher flexibility than the magnet between the tooth-shaped magnetic poles as the retaining members is also proposed (For example, see JP-A-2000-139045). However, since the plates having higher flexibility than the magnet are used for covering, the effect for preventing deformation of the magnets or the magnetic poles is insufficient.
Furthermore, in the related art in which the magnets are fixed to the tooth-shaped magnetic poles using the magnetic retaining members, a measure to constrain deformation by forming the retaining members into a shape which can receive a moment of the magnet generated during rotation or, at a high-speed revolution, by configuring the retaining members to come into contact with each other has been studied.
However, since the adjacent magnetic poles are not restrained in the radial direction directly, radially outward deformation increases (For example, see JP-A-2001-086715).